I. Field of the Invention
The present invention relates generally to pliers and similar hand manipulated tools where the movement ot handle elements of the tool causes a corresponding movement in jaw elements of the tool. More particularly, the present invention relates to pliers and like hand tools that have a long working length and include multiple pivot points between the jaw elements of the tool and the point where the tool is engaged by the hand.
II. Description of the Prior Art
The prior art is replete with different types of hand tools for use in particular applications. Many such prior art tools fall under the general category of pliers, wherein the tools have working jaws, handle elements and at least one pivot point, whereby the movement of the handle elements is directly proportional to the movement of the working jaws. Traditional pliers only have a single pivot point. The primary purpose of traditional pliers is to provide a mechanical advantage in gripping force so that a person using the pliers can manually turn a nut or perform a similar task. A major disadvantage with single pivot traditional pliers is that in order to open the jaws of the pliers widely, the handle elements of the pliers must also be opened widely. Such configurations therefore limit the application of traditional pliers and other currently manufactured pliers to situations where there is a relatively wide area of space available to manipulate the pliers. However, if an object to be worked upon is in a restricted area having a diameter less than two inches and a depth of more than three inches, then many traditional single pivot pliers cannot be used. In such applications, currently available deep reach pliers such as "needle nose" or "duckbill" pliers would have to be used in order to reach the object at the bottom of the restricted enclosure. Such currently available deep reach pliers also only have a single pivot. As a result, with a needed jaw opening width of at least 1/4 inch, such deep reach pliers typically only would have an effective reach in a restricted enclosure of up to four inches.
Those common types of deep reach pliers on the market today include elongated jaw and/or handle elements, such as those embodied, for example, in the Craftsman Power and Hand Tools caitalog, 1996-1997, page 52, the MAC Tools catalog, 1997, page 114, The Snap-On 75th Anniversary catalog, 1995, page 160 and the MATCO Tools Professional Hand Tools and Service Equipment Catalog, page 150. Since such single pivot deep reach pliers have elongated jaws, the mechanical advantage of such deep reach pliers is often less than 2:1. Consequently, even if an object is reachable by these currently available deep reach pliers, the pliers may not be able to manipulate the object. Moreover, the longer the jaw elements, the more flexible they become and thus there is a limited amount of twisting motion or torque that can be applied using such tools.
Recognizing the physical liiitations of traditional single pivot pliers and other tools, many tools in the prior art have adapted a construction where multiple pivot points exist between the handles of the tool and the jaws of the tool. A common application of such a tool is a bolt cutter. In traditional bolt cutters, multiple pivots are used to create an extremely large mechanical advantage at the jaws. As such, the gained mechanical advantage enables a person's manual force to cut the hardened steel of a bolt or padlock. However, in order to create such large mechanical advantages, bolt cutters must be configured so that a large movement in the handles results in only a small movement in the jaws. As a result, in order to open the jaws of a bolt cutter wide enough to engage a bolt, the handles of a bolt cutter may have to be opened well over twenty times as wide as the jaws. Consequently, the multi-pivoted construction of bolt cutters cannot be adapted to pliers that work in highly space restricted areas.
Another application of plier-like tools that have multiple pivot points is tongs. Unlike pliers, the purpose of tongs is to generally grasp an object for the purpose of moving the object. As such, tongs are generally designed to provide little or no mechanical advantage to its jaws. Many types of tongs, such as the tongs exemplified by U.S. Pat. No. 1,337,101 to Stovall, entitled TIE HANDLING TONGS and U.S. Pat. No. 718,790 to Pervier, entitled ICE TONGS provide mechanical advantages of 1:1 or less. A common feature of tongs is that the jaws of tongs must open widely in order for the tongs to engage whatever object the tongs were designed to engage. In order to design a multi-pivoted tong that is capable of having wide opening jaws, the tongs must be designed so that either the handles of the tongs open widely or the pivot joints of the tongs spread widely during use. Since such tongs either spread widely and/or provide no significant mechanical advantage, the configuration of such tongs cannot be adapted to pliers that must operate in a confined area and must provide a significant mechanical advantage. Such is the case with the tongs exemplified in U.S. Pat. No. 727,279 to Brindos entitled LOGGING OR TIE HANDLING TONGS, where the jaw elements open to a width that is greater than the width of the pivot elements. This fact, combined with the general structure of the Brindos tool, which includes, for example, handle elements at pivot locations would make the Brindlos tool inappropriate for accessing a restricted area.
Pliers with multiple pivot points do exist as is exemplified by U.S. Pat. No. 2,507,710 to Grosso, entitled ADJUSTABLE-ANGLE SURGICAL INSTRUMENT and U.S. Pat. No. 557,480 to Boyd, entitled SKELP TONGS. Such prior art devices do provide a mechanical adsiantage to the jaws of the pliers. However, in each case, the middle of the three pivot junctions must open to a width significantly wider than the plier jaws. Consequently, the width of the middle pivot junction is wider than the jaws and prevents the application of the pliers to highly restricted areas.
There are many applications where a tool such as a pair of pliers, a cutter, a clamp or other like tool must be applied deep within a narrow opening. Mechanics often come across such situations. In such situations, a wide tool simply cannot be used because the wide tool will not physically fit into the space available. For example, most presently manufactured automobiles, trucks, as well as aircraft, have extensive metal tubing, rubber hoses, air conditioning lines, wiring harnesses and the like which can substantially block access to the mechanicals below. In applications such as surgery, surgeons must often reach deep into the body during surgery. In order to limit the size of incisions and reduce trauma to surrounding tissues and organs, tools are required that are as narrow as possible.
In view of the prior art, a long felt need exists in the prior art for pliers and similar tools that are capable of being used in highly restricted areas, yet provide a significant mechanical advantage in gripping force. This need has not been readily met by the tools in the described prior art, nor has it been met by tools from leading tool manufacturers which are on the market today. Such a need is met by the present invention as described and claimed below.